Polyfill DOMException (#341)

Fixes #337 and livekit/client-sdk-js#1871.

Author: davidliu

.changeset/tough-cities-make.md

@@ -0,0 +1,5 @@
+---
+'@livekit/react-native': patch
+---
+
+Polyfill for DOMException to handle usage in livekit-client

src/index.tsx

@@ -1,6 +1,7 @@
 import 'well-known-symbols/Symbol.asyncIterator/auto';
 import 'well-known-symbols/Symbol.iterator/auto';
 import './polyfills/MediaRecorderShim';
+import './polyfills/DOMException';
 import { registerGlobals as webrtcRegisterGlobals } from '@livekit/react-native-webrtc';
 import { setupURLPolyfill } from 'react-native-url-polyfill';
 import './polyfills/EncoderDecoderTogether.min.js';

src/polyfills/DOMException.ts

@@ -0,0 +1,21 @@
+/**
+ * DOMException is missing in some React Native / JS runtimes but is required by
+ * web APIs (e.g. AbortController, fetch) that may be used in livekit-client.
+ */
+    
+// @ts-expect-error: global may not declare DOMException in RN types.
+if (typeof global.DOMException === 'undefined') {
+  class PolyfillDOMException extends Error {
+    readonly code: number;
+  
+    constructor(message = '', name?: string) {
+      super(message);
+      this.message = message;
+      this.name = name ?? 'Error';
+      this.code = 0;
+      Object.setPrototypeOf(this, PolyfillDOMException.prototype);
+    }
+  };
+  // @ts-expect-error
+  global.DOMException = PolyfillDOMException;
+}